In 1665, the British scholar Robert Hooke designed and manufactured the first optical microscope with a magnification of 40 to 140 times, and used this to observe and describe plant cells for the first time. In the same year, he published the book "Micrograph".

　　 After that, the Dutch scholar A.V. Leeuwenhoek observed animal cells with a more advanced microscope designed by himself and described the morphology of the cell nucleus. Until today, optical microscopy technology has evolved from ordinary compound optical microscopy to fluorescence microscopy, confocal laser scanning microscopy technology, digital imaging microscopy technology, dark field microscopy technology, phase contrast and differential interference microscopy technology and video to increase contrast Microscope technology and more.

　　It can be seen that optical microscopy has become a necessary tool for humans to understand the microscopic world. With the help of it, people can understand cells. However, accurate theoretical calculations show that the quality of optical microscopes has not improved--no matter how many sets of lenses are used, oil lenses are used or the light source is strengthened, the magnification is at most 1000~1500, and the resolution is at most. This has become a bottleneck problem for humans to recognize smaller objects: viruses, molecules, and atoms.

　　 The famous physicist Helen Hall et al. theoretically proved that the factor that limits the resolution and magnification of an optical microscope is the wavelength of light. Therefore, people turn to looking for an imaging medium-wave, which has the characteristics of being visible, capable of taking pictures, short wavelength, and capable of changing the wave's motion route with a device.

　　 At the beginning of the 20th century, Chais invented the ultraviolet light microscope, which greatly improved the resolution. This is a qualitative leap, but ultraviolet light is still not the best imaging medium and cannot meet the needs of scientific research and production.

　　 In 1926, the German scientist Pusch pointed out that the axially symmetrical magnetic field acts as a lens on the electron beam. Unfortunately, the researchers did not consider using it to magnify objects.

In 1932, young researchers Luca and Knorr of the Pressure Laboratory of the Berlin University of Science and Technology made some improvements to the cathode ray oscilloscope and successfully obtained the copper mesh image magnified several times. This greatly encouraged people and established the electron microscope law.

　　 At the end of 1933, Lucca built an electron microscope that can magnify 10,000 times and took a magnified image of metal foil and fiber. The magnification of the electron microscope exceeds that of the optical microscope.

In 1937, Clauser and Müller of the Berlin University of Science and Technology successfully produced an electron microscope with a resolution of nanometers (10-9m). When Siemens learned about it, they focused their efforts on the manufacture of suitable electron microscopes. , And hired Luce to conduct research. In the following year, Siemens' first batch of electron microscopes with a resolution of 1 Å was listed.

　　 Subsequently, under people's research, the quality of electron microscopes has been continuously improved. Today, its resolution and magnification allow people to more accurately understand viruses, molecules, atoms, and quarks.